Physics Chapter 21 Notes

Temperature, Heat, & Expansion

• Chapter 21 Terms & Objectives
• Concepts (PowerPoint presentation)
  • Temperature - related to average KE of molecules
    • Fahrenheit scale
    • Celsius scale
    • Kelvin scale
  • Internal Energy - total KE and PE of molecules
  • Heat - transfer of internal energy due to a temperature difference
    • compare to Work - transfer of energy due to a force
    • If there is thermal contact, heat "flows" from high temperature to low temperature until thermal equilibrium is reached.
    • 1 calorie = heat to raise temperature of 1 gram of water by 1^o Celsius = 4.2 Joules
    • 1 Calorie = 1000 cal (diet calorie)
  • Specific Heat Capacity
    • amount of energy need to raise the temperature of 1 gram of a substance by 1^oC
    • high specific heat capacity
      • lots of energy required to raise the temperature
    • lots of energy available at high temperature
    • Water's specific heat capacity is high (1 cal/gram^oC)
    • low specific heat capacity
      • large rise in temperature for a little added energy
    • not much heat energy available even at high temperatures
  • Solving heat transfer problems
  • 
  • Example
  • Expansion
    • most substances expand when heated
      • solids least, gasses most
    • water's behavior is unusual
      • maximum density at 4^oC
        • pond freezing
• Lab & Demos:
  • Demo: Expansion of Gasses, Liquids, and Solids
• Specific Heat of a Metal
• Links
  • CPSurf.com - annotated links keyed to your textbook